Electron energy loss spectroscopy and x-ray microanalysis have been used to study the elemental composition in sections of rat ameloblasts (enamel-forming cells). Calcium has been found in the secretory granules near the Tomes' processes in cells treated with potassium pyroantimonate (a precipitation agent). The immature enamel has also been investigated to estimate the fraction of protein matrix that is present. Preliminary results have been obtained showing elemental energy loss maps of the calcium concentration.